Fluid-pump for multicylinder internal-combustion engines



K. J. E. HESSELMAN. FLUID PUMP FOR MULTICYUNDER INTERNAL comsusnou ENGINES.

APPLICATION FILED JAN. 2|, l9l9.

Patented Aug. 3, 1920.

I aid of UNITED STATES PATENT OFFICE.

KN UT JONAS ELIAS HESSELMAN, OF SALTSJ'fi-STORANGEN, SWEDEN.

Application filed January 21, 1919.

To a whom it may concern.

lie it known that I, Kxu'r Jonas ELIAS linssnmmx, a citizen of the Kingdom of Sweden, residing at Saltsjostoriingen, Sweden, have invented new and useful 1mprovements in Fluid-Pumps for Multicylinder Internal-Combustion Engines, of which the following is a specification.

()ne of the most important problems in constructing multi-cylinder internal combustion engines using liquid fuels, consists in the provision of means for uniform dis tribution of the fuel to the various cylinders. 111 machines in which the fuel is supplied under pressure, the distribution of the fuel to the various cylinders is usually accomplished by the aid of a separate pump for each cylinder. However, in some cases, especially in Diesel engines, it has been proposed to use one pump for a plurality of cylinders and to distribute the fuel supplied by said pump by means of a special distributing device communicating by pipes or conduits with the various cylinders. The distribution is effected in this case by causing the oil in the distributer to pass small, calibrated apertures before entering the said pipes. The resistance in said small apertures is so great that the differences in pressure eventually occurring in the fuel valves, and the differences in resistance which may occur in the said pipes will be exceedingly small in relation to the resistances in the said small apertures.

The said device for distributing the fuel cannot, however, be used in connection with reversible engines as the distribution of the fuel when the direction of movement of the engine is reversed, or when the engine is running at low speed is unreliable, nor can it be used in engines in which the fuel is injected direct into the cylinder without the air under pressure.

In internal combustion engines of the last mentioned kinds it has hitherto been necesary to use a separate pump for each cylinder. It is obvious, that the exact distribution of the fuel to the various cylinders of such an engine, particularly while running at light load when the quantities of fuel to be supplied are very small, requires a very minute adjustment of members subjected to wear or which otherwise may easily be brought out of the condition which enables exact distribution. Said adjustment difficulties necessarily will be much greater in engines Specification of Letters Patent.

Patented Aug. 3, 1920. Serial No. 272,251.

in which the fuel is injected direct into the cylinder without the aid of pre-explosion chambers of any kind. In such engines also the moment at which the injection should begin must be much more exactly adjusted and much easier to vary according to different loads and dilferent kinds of fuel than in other engines.

It is obvious, that if it were possible to use a single pump, that is, a single plunger, and a single set of regulating valves for feeding all of the cylinders, the exactness of the fuel (.listribution would be secured under all conditions, and the adjusting of the moment of injection would be facilitatcd.

Said object will be attainedaccording to this invention by using a fuel supply pump common to all of the cylinders and causing it to perform for each revolution of the crank shaft of the engine a plurality of pressure strokes corresponding to the number of ignitions, the pump casing or a chamber communicating therewith being connected toeach cylinder through a pipe or conduit containing a valve mechanically controlled in such a way that all valves will be opened in succession for supplying fuel to their respective cylinders at each pressure stroke of the pump. In a four stroke engine having, for instance, six cylinders. the number of revolutions of the pump will be three times the number of revolutions of the engine shaft while in a two stroke engine having six cylinders. the number of revolutions of the pump will be six times the number of revolutions of the engine shaft.

In the accompanying drawin illustrating the invention, Figures 1, 2 and l show diagrammatic sections through three different embodiments of the invention as applied to a two stroke engine having six cylinders. Fig. 4 shows a diagram illustrating the operation of the embodiment shown in Fig. 2.

In the embodiment shown in Fig. l, the shaft 1 is assumed to be connected to the crank-shaft of the engine and to rotate with the same number of revolutions as the crank-shaft. The shaft 1 is connected by means of the gear 7. 8 to a shaft 9 in turn connected through the crank 10, the conneoting rod 11 and the cross-head 12, to a plunger 13 reciprocating in the pump casing 14. The ratio of gearing between the toothed wheels 7 and 8 is so chosen that the shaft 9 will perform six revolutions for each revolution of the shaft 1. The pump casing 14 is provided with a suction valve 16 and a pressure valve 15, the latter controlling the connection between the ump casing and a distributing box 18 whi e the valve 16 controls the communication between the pump casing and a suction pipe 17. Connected to the distributing box 18 are six pipes 19, leading each to one of the cylinders of the engine (not shown In each of said pipes 19 a spring controlled valve 20 is provided adapted to be opened by a sliding rod 21 operated by a crank 24 on the shaft 1 through the intermedium of a cross-head 22 and a connecting rod 23. The six cranks 24 are so arranged that all of the valves 20 will open in succession one time for each revolution of the shaft 1 and at times adjusted according to the operation of the different cylinders. While the valves 20 are thus opened in succession, the plunger 13 performs six pressure strokes and six suction strokes and at each stroke one of the valves 20 is kept open so as to allow fuel to be pressed into the pi e leading to the correspondin cylinder. n each revolution of the shaft 1 each cylinder will thus receive a determined quantity of fuel which is equal for all of the cylinders, the arrangement being further such that the opening of eachvalve 20 takes place somewhat before the beginning of the corresponding pressure stroke, while the closing of the valve takes place somewhat after the completion of the pressure stroke. By this arrangement the valve is kept open uring the whole pressure stroke. Variation of the quantity of fuel supplied may be effected for instance by regulating the stroke of the plunger 13 or by adjusting the suc' tion valve or in any other suitable way. Said construction is suitable for Diesel engines and some other types of engines. In engines of the kind in which the fuel is injected without the aid of air under pressure and in which no pre-explosion chamber is provided a somewhat modified pump construction is to be preferred. Two suitable embodiments of such modified pump constructions are shown in Figs. 2 and 3.

In the embodiment shown in Fig. 2, a mechanically controlled valve. 25 is provided between the pump casing and the distributing box 18, the pump casing being in this embodiment provided with an overflow valve 26. The valve 25 is opened when the pump has performed part of its pressure stroke and is closed before the end of the pressure stroke. \Vhen the valve 25 is closed, the quantity of fuel supplied by the plunger is caused to return to the suction pipe through the valve 26. The operation of the mechanism will be as follows reference being had to the diagram shown in Fig. 4. In said diagram the arc between driven and by providin two radii corresponds to one pressure stroke and one suction stroke of the plunger. Durin the suction stroke a valve 20 is opene at the point 1 at 1 the pressure stroke commences, from 1 to 1 fuel is pressed through the valve 26, the valve 25 being closed. At 1 the valve 25 is opened, from 1 to 1" fuel is pumped through the valve 25 into the distributing box 18 and through that one of the valves 20 momentarily open into the corresponding pipe 19. At 1* the valve 25 is closed and at 1 the pressure stroke ceases. At 1 the valve 20 previously open is closed, whereupon the play described will be repeated and fuel be forced through the next valve 20, and

so on.

In the arrangement illustrated in Fig. 3, a usual pressure valve 15 is provided be- .tween the pump casing 14, and the distributing box, furthermore a mechanically controlled suction valve 27 is provided serving to allow part of the fuel supplied by the plunger 13 to return, at the beginning of the pressure stroke as well; as at the end thereof, to the suction pipe said valve 27 being open during the suction stroke and admitting alone or together with a usual suction valve 16 the oil to the pump casing. The operation of this embodiment corresponds to that described above with reference to the embodiment illustrated in Fig. 2.

Variation of the quantity of fuel supplied in the embodiments shown in Figs. 2 and 3 may be effected by varying the length of the plunger stroke or bymeans of suitable regulating devices controlling the valves 25 and 27.

Instead of the cranks shown for operating the valves and the plunger I may use suite ably formed cam disks or eccentrics.

From a practical point of view it may be preferred to have the plunger perform for instance twice as many strokes as corresponds to the number of ignitions. This may readily be attained by driving the cranks or the eccentrics or the like operating the valves 25 and 27 at half the number of revolutions as that at which the pump is means whereby every second pressure stro e is skipped over and the wholequantity of fuel is returned to the suction pipe through the valves 26 and 27, respectively. Such a pump, device may also be applied to an engine having one cylinder only in which case most of the pressure strokes of the pump are made ineffective.

It should be noted that other modifications of the invention may be made without departing from the scope or principle thereof.

or instance, the valve between the pump casing and the distributing box may be omitted and replaced by a pressure valve in each of the pipes leading from the distributing box. It is obvious, that in such case no separate pump casing is required inasmuch as the plunger may work direct in the distributing box.

Having thus described my invention, what I claim is 2-- 1. The combination with a multi-cylinder internal combustion engine, of a shaft connected to the crank shaft of an engine, gears secured to said shaft, a plunger secured to the shaft by a rod and cross-head, said plunger reciprocating in a pump casing, a suction valve and ressure valve provided in.said pump caslng, a distributing box communicating with the pump casing and controlled by the pressure valve, a suction pipe communicating with the pump casing and controlled by the suction valve of the pump casing, a plurality of pipes connected with the distributing box and leading each to one cylinder of the engine, a springcontrolled valve provided in each of the pipes, a rod adapted for opening each of said spring-controlled valves, and an auxiliary shaft, connected to the shaft that is secured to the crank shaft of the engine for operating said last named rods, whereby when one revolution of the engine crank shaft takes place, each of the spring valves of the pipes will be opened in succession, substantially as and for the purpose set forth.

2. The combination with a multi-cylinder internal combustion engine, of a single fuel supply pump, a chamber communicating with said pump, a valve between said pump and said chamber for preventing fuel from flowing back from the chamber into the pump, a plurality of fuel supply pipes, one for each cylinder of the engine, communicating with said chamber, a plurality of valves each controlling one of said pipes, means driven from the crank shaft of the engine for operating the valves in succession, and means for operating the ump so as to cause it to perform a comp ete cycle of operations for each operation of said successively operating valves, substantially as and for the purpose set forth.

3. The combination with a multi-cylinder internal combustion engine, of a single fuel supply pump, a chamber communicating with said pump, a valve between said chamber and said pump for preventing fuel from flowing back from the chamber into the pump, a mechanically operated valve for controlling the amount of fuel to be fed to the chamber at each pressure stroke of the pump, a plurality of fuel supply pipes, one for each cylinder of the engine, communicating with said chamber, a plurality of valves each controlling one of said pipes, means driven from the crank shaft of the engine for o erating the valves in succession, and means or operating the pump so as to cause it to perform a complete cycle of operations for each operation of said successively operating valves, substantially as and for the purpose set forth.

In testimony whereof I have signed my name.

KNUT JONAS ELIKS HESSELHAN. 

